The invention relates to an apparatus for the winding of a web of material, such as paper, comprising two supporting rolls each driven by a motor and having a gap therebetween wherein the spool on which the web of goods is to be wound is pressure biased by a pressure roll, and control means for the motors which preferably, as the coil diameter increases, increases the torque of the motor of the first supporting roll in the direction of the movement of the web and diminishes the torque of the motor of the second supporting roll in the direction of movement of the web.
In a known apparatus for the winding of a web of goods, the two supporting rolls are coupled together by a gear drive and are driven by a single motor. To enable the web of goods to be wound with the desired tightness, the supporting rolls are rotated at a slight difference in their circumferential speed. It has been found that in such an apparatus the spool runs roughly on the supporting rolls and consequently the quality of the winding of the web of goods is unsatisfactory.
In another apparatus for the winding of webs of goods, in which the two rolls are also driven by only one motor, the supporting rolls are coupled together by a belt drive. This type of coupling results in a smoother running and in a better coil quality.
Disadvantageous to the coil quality in both of the known apparatus is the stiff coupling of the two supporting rolls. Attempts have been made to eliminate this disadvantage with another known apparatus.
In this apparatus, each supporting roll is associated with a motor of its own. The torque of the two motors is controlled in relation to the coil diameter such that the motor associated with the first supporting roll in the direction of movement of the web is operated with an increasing torque and the motor associated with the second supporting roll in the direction of movement of the web is operated with a decreasing torque. With such an apparatus it is in principle possible to wind the web of goods with a tightness which diminishes from the core out. But in this apparatus, the results of the winding are unsatisfactory, because during the winding, the coil oscillates on the supporting rolls.